The present invention relates to a double barrier heat exchanger more particularly intended for the cooling of the radioactive primary water of a sampling circuit of a water reactor, which in particular makes it possible to detect a leak of the primary liquid in said exchanger.
A certain number of auxiliary circuits are connected to the primary circuit of a nuclear reactor and make it possible to check the satisfactory operation of the primary circuit and, if necessary, adjust the characteristics of the primary fluid. With regards to one of these circuits, called the sampling circuit used for sampling the primary liquid for analysis purposes, it is neccessary to cool the primary liquid from the core before carrying out the sampling operation. For this purpose, cooling takes place by means of a secondary cooling circuit. Most of the presently used exchangers do not completely protect the secondary circuit against risks of pollution by the primary fluid and generally do not make it possible to rapidly detect an accidental leak in the latter.